There are 3 papers:
STEP I is on A Level Maths content.
STEP II is on AS Level Further Maths content.
STEP III is on A Level Further Maths content.
I do know that but is it advisable for year 12 to take the exams(all 3 as I have finished maths and most further maths a-level syllabus currently working through all the modules)
what are the usual "standard offers " in terms step from Warrick and Durham for bachelors maths and masters math
Standard offer for Warwick with STEP is A*A*A + 1 in STEP.
Durham's offer is A*AA + 1 in STEP or suitable performance in MAT/TMUA. (while I assume at this level you'll be mainly looking at C/O firm [if you get an offer], W/I insurance some do choose to go elsewhere)